U.S. patent application number 15/509323 was filed with the patent office on 2017-09-07 for fuel injection valve.
The applicant listed for this patent is DENSO CORPORATION. Invention is credited to Shinobu OIKAWA, Shinsuke YAMAMOTO.
Application Number | 20170254304 15/509323 |
Document ID | / |
Family ID | 55532809 |
Filed Date | 2017-09-07 |
United States Patent
Application |
20170254304 |
Kind Code |
A1 |
YAMAMOTO; Shinsuke ; et
al. |
September 7, 2017 |
FUEL INJECTION VALVE
Abstract
In a fuel injection valve, when a regulating unit provided in a
needle abuts against a movable core, a gap is defined between a
flange portion end face of a flange portion and a movable core
first end face of the movable core. With the above configuration,
when a coil develops a magnetic field, because the movable core
abuts against a flange portion while accelerating in a
valve-opening direction, a relatively large force is exerted on the
needle in the valve-opening direction. The needle is further moved
in the valve-opening direction by an urging force of a second
spring after the movable core has abutted against the fixed core.
With the above configuration, a lift quantity of the needle is
longer than a distance by which the movable core moves until the
movable core abuts against a fixed core abutting portion since the
movable core abuts against the flange portion. As a result, the
lift quantity of the needle can be increased without any increase
in the electric power to be supplied to the coil.
Inventors: |
YAMAMOTO; Shinsuke;
(Kariya-city, JP) ; OIKAWA; Shinobu; (Kariya-city,
JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
DENSO CORPORATION |
Kariya-city, Aichi-pref. |
|
JP |
|
|
Family ID: |
55532809 |
Appl. No.: |
15/509323 |
Filed: |
September 14, 2015 |
PCT Filed: |
September 14, 2015 |
PCT NO: |
PCT/JP2015/004678 |
371 Date: |
March 7, 2017 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F02M 51/066 20130101;
F02M 51/0653 20130101; F02M 51/061 20130101; F02M 51/06 20130101;
F02M 61/042 20130101 |
International
Class: |
F02M 51/06 20060101
F02M051/06 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 17, 2014 |
JP |
2014-188846 |
Claims
1. A fuel injection valve comprising: a housing that has an
injection hole that is defined on one end in a central axis and
injects a fuel, and a valve seat that is formed around an opening
of the injection hole; a fixed core that is fixed to an inside of
the housing; a needle member that is disposed to be reciprocatingly
movable in the housing, closes a valve when one end portion of the
needle member abuts against the valve seat, and opens the valve
when the one end portion of the needle member is lifted from the
valve seat; a flange portion that is disposed radially outside of
the other end portion of the needle member to be reciprocatingly
movable integrally with the needle member; a movable core that is
disposed to be movable relative to the needle member on the valve
seat side of the flange portion; a regulating unit that is disposed
radially outside of the needle member on the valve seat side of the
movable core to be reciprocatingly movable integrally with the
needle member, and abuts against the movable core to regulate the
movement of the movable core in the valve-closing direction; a coil
that develops a magnetic field to cause the movable core to be
attracted to the fixed core when receiving an electric power; a
first urging member that urges the needle member in the
valve-closing direction; and a second urging member one end portion
of which abuts against the regulating unit to urge the needle
member in the valve-opening direction through the regulating unit,
wherein when the regulating unit abuts against the movable core, a
gap is defined between the flange portion and the movable core.
2. The fuel injection valve according to claim 1, further
comprising: a flange portion accommodation member that has an end
portion on the valve seat side formed to be abuttable against the
movable core, and which houses the flange portion to be
reciprocatingly movable, wherein the first urging member has one
end portion abutted against the flange portion accommodation
member, and urges the needle member in the valve-closing direction
through the flange portion accommodation member, the movable core,
and the regulating unit.
3. The fuel injection valve according to claim 2, wherein the
flange portion accommodation member is formed in a bottomed tubular
shape, and the flange portion accommodation member includes a
bottomed portion against which one end portion of the first urging
member abuts, and a cylinder portion that extends in a direction of
the valve seat from the bottomed portion, and has an end portion on
the valve seat side formed to be abuttable against the movable
core.
4. The fuel injection valve according to claim 3, wherein the
cylinder portion includes an inner wall that slides on an outer
wall on a radial outside of the flange portion.
5. The fuel injection valve according to claim 4, wherein the inner
wall of the cylinder portion is identical in hardness with the
outer wall of the flange portion.
6. The fuel injection valve according to claim 3, wherein the
cylinder portion has an outer wall that slides on an inner wall of
the fixed core.
7. The fuel injection valve according to claim 6, wherein the inner
wall of the fixed core is identical in hardness with the outer wall
of the cylinder portion.
8. The fuel injection valve according to claim 1, wherein the
housing has a slide member that is disposed on the valve seat side
of the regulating unit, and has an inner wall sliding on an outer
wall of the needle member.
9. The fuel injection valve according to claim 1, further
comprising a third urging member that has one end abutted against
the movable core, and the other end abutted against an inner wall
of the housing, and urges the movable core in the valve-opening
direction.
10. The fuel injection valve according to claim 1, wherein the
fixed core includes an abutting portion that has the same hardness
as that of the movable core, and is abuttable against the movable
core.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] This application is based on Japanese Patent Application No.
2014-188846 filed on Sep. 17, 2014, the disclosure of which is
incorporated herein by reference.
TECHNICAL FIELD
[0002] The present disclosure relates to a fuel injection valve for
injecting a fuel into an internal combustion engine.
BACKGROUND ART
[0003] Up to now, a fuel injection valve in which an injection hole
provided in a housing is opened and closed by a reciprocating
motion of a needle, and a fuel in the housing is injected toward an
outside has been known. For example, Patent Literature 1 discloses
a fuel injection valve in which when the needle is abutted against
a valve seat formed around an inner opening of the injection hole,
a gap having a predetermined distance in a center axis direction of
the housing is provided between the needle and a movable core.
[0004] In the fuel injection valve disclosed in Patent Literature
1, the movable core is moved in a valve-opening direction and
abutted against the needle while being accelerated by a magnetic
attraction force exerted between the movable core and a fixed core
with the use of the gap between the movable core and the needle.
With the above configuration, in the fuel injection valve disclosed
in Patent Literature 1, a relatively large force for opening the
valve is exerted on the needle.
[0005] However, in the fuel injection valve disclosed in Patent
Literature 1, a distance by which the movable core moves after the
movable core has been abutted against the needle when a valve is
opened is identical with a distance (hereinafter referred to as
"lift quantity") by which the needle moves. For that reason, when
the injection quantity of fuel is increased with an increase in the
lift quantity, the distance by which the movable core moves after
the movable core has been abutted against the needle must been
lengthened, resulting in a need to increase a power to be supplied
to a coil for generation of a magnetic field. Hence, there is a
risk that a power consumption of the fuel injection valve is
increased.
PRIOR ART LITERATURES
Patent Literature
[0006] Patent Literature 1: Japanese Patent No. 4637930
SUMMARY OF INVENTION
[0007] It is an object of the present disclosure to provide a fuel
injection valve capable of increasing an injection quantity of fuel
with a small power consumption.
[0008] A fuel injection valve according to the present disclosure
includes a housing, a fixed core, a needle member, a flange
portion, a movable core, a regulating unit, a coil, a first urging
member, and a second urging member. The needle member is disposed
to be reciprocatingly movable in the housing, the valve is closed
when one end portion of the needle member abuts against the valve
seat, and the valve is opened when one end portion of the needle
member is lifted from the valve seat. The flange portion is
disposed radially outside of the other end portion of the needle
member so as to be reciprocatingly movable integrally with the
needle member. The movable core is disposed to be movable relative
to the needle member on the valve seat side of the flange portion.
The regulating unit is disposed radially outside of the needle
member on the valve seat side of the flange portion so as to be
reciprocatingly movable integrally with the needle member, and can
regulate the movement of the movable core in the valve-closing
direction when abutting against the movable core. The first urging
member urges the needle member in the valve-closing direction. The
second urging member has one end abutting against the regulating
unit, and urges the needle member in the valve-opening direction
through the regulating unit. In the fuel injection valve according
to the present disclosure, when the regulating unit abuts against
the movable core, the gap is defined between the flange portion and
the movable core.
[0009] In the fuel injection valve according to the present
disclosure, when the regulating unit abuts against the movable
core, the gap is defined between the flange portion and the movable
core. When the power is supplied to the coil at the time of opening
the valve, the movable core moves while accelerating in the
valve-opening direction with the use of the gap, and abuts against
the flange portion. As a result, the relatively large force in the
valve-opening direction can be exerted on the needle.
[0010] In addition, in the fuel injection valve according to the
present disclosure, the second urging member abuts against the
regulating unit disposed radially outside of the needle member so
as to be reciprocatingly movable integrally with the needle member.
The second urging member urges the needle member in the
valve-opening direction through the regulating unit. In the case
where the movable core is attracted to the fixed core to open the
fuel injection valve, when the movable core abuts against the fixed
core after the movable core moving in the valve-opening direction
has abutted against the flange portion, the needle member is spaced
apart from the movable core due to the urging force of the second
urging member, and further moves in the valve-opening direction. As
a result, the lift quantity of the needle member is longer than the
distance by which the movable core moves until the movable core
abuts against the fixed core since the movable core abuts against
the flange portion. Therefore, in the fuel injection valve
according to the present disclosure, the lift quantity of the
needle member is increased without any increase in the electric
power to be supplied to the coil, as a result of which the
injection quantity of fuel can be increased.
BRIEF DESCRIPTION OF DRAWINGS
[0011] The above-described purpose and the other purposes of the
present disclosure, as well as the features and advantages of the
present disclosure, will be further clarified in the following
detailed description and with reference to accompanying
drawings.
[0012] FIG. 1 is a cross-sectional view of a fuel injection valve
according to a first embodiment of the present disclosure.
[0013] FIG. 2 is an enlarged view of a part II in FIG. 1.
[0014] FIG. 3 is an enlarged view of a part II in FIG. 1, which
illustrates an action different from that in FIG. 2.
[0015] FIG. 4 is an enlarged view of a part II in FIG. 1, which
illustrates an action different from that in FIGS. 2 and 3.
[0016] FIG. 5 is an enlarged view of a part II in FIG. 1, which
illustrates an action different from that in FIGS. 2, 3, and 4.
[0017] FIG. 6 is a characteristic diagram illustrating a
relationship between a lift quantity of a needle and a force
exerted on the needle in the fuel injection valve according to the
first embodiment of the present disclosure.
[0018] FIG. 7 is a cross-sectional view of a fuel injection valve
according to a second embodiment of the present disclosure.
[0019] FIG. 8 is a cross-sectional view of the fuel injection valve
according to the second embodiment of the present disclosure, which
illustrates an action different from that in FIG. 7.
[0020] FIG. 9 is a cross-sectional view of a fuel injection valve
according to a third embodiment of the present disclosure.
[0021] FIG. 10 is a cross-sectional view of a fuel injection valve
according to a third embodiment of the present disclosure, which
illustrates an action different from that in FIG. 9.
[0022] FIG. 11 is a cross-sectional view of a fuel injection valve
according to a fourth embodiment of the present disclosure.
EMBODIMENTS FOR CARRYING OUT INVENTION
[0023] Hereinafter, embodiments of the present disclosure will be
described with reference to drawings.
First Embodiment
[0024] A fuel injection valve 1 according to a first embodiment of
the present disclosure is illustrated in FIGS. 1 to 6. FIGS. 1 to 5
illustrate a valve-opening direction and a valve-closing direction
in which the valve-opening direction is a direction in which a
needle 40 is spaced apart from a valve seat 255 and the
valve-closing direction is a direction in which the needle 40 abuts
against the valve seat 255.
[0025] A fuel injection valve 1 is used in a fuel injection device
for a direct injection gasoline engine not shown and injects a
gasoline as a fuel into an engine with a high pressure. The fuel
injection valve 1 includes a housing 20, the needle 40, a movable
core 50, a fixed core 30, a coil 35, a first spring 31 as a "first
urging member", a second spring 32 as a "second urging member", and
so on. Incidentally, the fuel injected by the fuel injection valve
according to the present disclosure is not limited to the gasoline.
The fuel may be a light oil.
[0026] As illustrated in FIG. 1, the housing 20 includes a first
cylinder member 21, a second cylinder member 22, a third cylinder
member 23, and an injection nozzle 25. Each of the first cylinder
member 21, the second cylinder member 22, and the third cylinder
member 23 is formed in a cylindrical shape, and the first cylinder
member 21, the second cylinder member 22, and the third cylinder
member 23 are coaxially disposed in the stated order and are
connected to each other.
[0027] The first cylinder member 21 and the third cylinder member
23 are made of a magnetic material such as ferritic stainless
steel, and subjected to a magnetic stabilization treatment. The
first cylinder member 21 and the third cylinder member 23 are
relatively low in hardness. On the other hand, the second cylinder
member 22 is made of a nonmagnetic material such as austenitic
stainless steel. The second cylinder member 22 is higher in
hardness than the first cylinder member 21 and the third cylinder
member 23.
[0028] The injection nozzle 25 is disposed on an end portion of the
first cylinder member 21 on a side opposite to the second cylinder
member 22. The injection nozzle 25 is formed in a bottomed
cylindrical shape, made of a metal such as martensitic stainless
steel, and welded to the first cylinder member 21. The injection
nozzle 25 is subjected to a quenching treatment so as to provide a
predetermined hardness. The injection nozzle 25 includes an
injection portion 251 and a cylinder portion 252.
[0029] The injection portion 251 is axisymmetrically formed with
respect to a central axis CA0 of the housing 20, which is coaxial
with a central axis of the fuel injection valve 1, as an axis of
symmetry. An outer wall 253 of the injection portion 251 protrudes
from an interior of the injection nozzle 25 in the direction of the
central axis CA0. The injection portion 251 has multiple injection
holes 26 that communicate an inside and an outside of the housing
20 with each other. A valve seat 255 is formed around openings
inside of the injection holes provided in an inner wall 254 of the
injection portion 251,
[0030] The cylinder portion 252 surrounds a radial outside of the
injection portion 251 and extends in a direction opposite to a
direction in which the outer wall 253 of the injection portion 251
protrudes. The cylinder portion 252 has one end portion connected
to the injection portion 251 and the other end portion connected to
the first cylinder member 21.
[0031] The needle 40 is made of a metal such as martensitic
stainless steel. The needle 40 is subjected to a quenching
treatment so as to provide a hardness comparable to the hardness of
the injection nozzle 25.
[0032] The needle 40 is housed in the housing 20 to be
reciprocatingly movable. The needle 40 includes a shaft portion 41
as a "needle member", a seal portion 42 as "one end portion of the
needle member", a flange portion 43, a regulating unit 45, and the
like. The shaft portion 41, the seal portion 42, the flange portion
43, and the regulating unit 45 are integrated together so as to be
reciprocatingly movable.
[0033] The shaft portion 41 is a rod-shaped portion, an end portion
of which on the fixed core 30 side is formed in a tubular shape. A
flow channel 400 is provided inside of the other end portion of the
shaft portion 41 on the fixed core 30 side, and the fuel flows in
the flow channel 400 toward the injection nozzle 25. The flow
channel 400 communicates with a hole 411 provided in the shaft
portion 41 on the valve seat 255 side of the flow channel 400. In
other words, the hole 411 allows the flow channel 400 to
communicate with an external of the shaft portion 41.
[0034] The seal portion 42 is disposed on the end portion of the
shaft portion 41 on the valve seat 255 side so as to be abuttable
against the valve seat 255. When the seal portion 42 is spaced
apart from the valve seat 255 or abuts against the valve seat 255,
the needle 40 opens or closes the injection holes 26, and allows or
blocks a communication between the inside and the outside of the
housing 20.
[0035] A sliding contact portion 44 is formed between the shaft
portion 41 and the seal portion 42. The sliding contact portion 44
is formed in a cylindrical shape and has an outer wall 441
partially chamfered. A portion of the outer wall 441 in the sliding
contact portion 44, which is not chamfered, is slidable on an inner
wall of the injection nozzle 25. With the above configuration, the
reciprocating movement of the needle 40 on a tip end portion on the
valve seat 255 side is guided.
[0036] The flange portion 43 is formed in a substantially toric
shape and is disposed radially outside the end portion of the shaft
portion 41 on the fixed core 30 side. The flange portion 43 is
formed to be larger in outer diameter than the shaft portion
41.
[0037] The regulating unit 45 is formed in a substantially toric
shape and disposed radially outside of the shaft portion 41 on the
valve seat 255 side of the flange portion 43 at a predetermined
distance from the flange portion 43. The regulating unit 45 is
formed to be larger in outer diameter than the shaft portion 41.
The movable core 50 is disposed to be reciprocatingly movable
between a regulating unit first end face 451 of the regulating unit
45 on the fixed core 30 side and a flange portion end face 431.
[0038] The movable core 50 is formed in a tubular shape and made of
a magnetic material such as ferritic stainless steel. The movable
core 50 is disposed on the valve seat 255 side of the fixed core 30
so as to be reciprocatingly movable relative to the housing 20.
[0039] The movable core 50 has a movable core through hole 500
through which the shaft portion 41 is inserted. A movable core
first end face 501 of the movable core 50 on the fixed core 30 side
is formed to be abuttable against the flange portion end face 431.
A movable core second end face 502 of the movable core 50 on the
valve seat 255 side is formed to be abuttable against the
regulating unit first end face 451. When the seal portion 42 abuts
against the valve seat 255, and the regulating unit first end face
451 abuts against the movable core second end face 502, a gap 430
is defined between the flange portion end face 431 and the movable
core first end face 501.
[0040] The fixed core 30 is welded to the third cylinder member 23
of the housing 20 and is fixed to the inside of the housing 20. The
fixed core 30 has a fixed core main body portion 301 and a fixed
core abutting portion 302.
[0041] The fixed core main body portion 301 is formed in a tubular
shape and made of a magnetic material such as ferritic stainless
steel. The fixed core main body portion 301 is subjected to the
magnetic stabilization treatment, and disposed in a magnetic field
developed by the coil 35 to be described later.
[0042] The fixed core abutting portion 302 is a cylindrical member
that is disposed inside of the fixed core main body portion 301 on
the valve seat 255 side. The fixed core abutting portion 302 has a
hardness comparable to hardness of the movable core 50. An end face
303 of the fixed core abutting portion 302 on the valve seat 255
side is located closer to the valve seat 255 side than an end face
304 of the fixed core main body portion 301 on the valve seat 255
side. With the above configuration, when the movable core 50 moves
in the valve-opening direction, the movable core first end face 501
of the movable core 50 abuts against the end face 303 of the fixed
core abutting portion 302 to regulate the movement of the movable
core 50 in the valve-opening direction.
[0043] The coil 35 is formed in a tubular shape and mainly
surrounds the radially outer sides of the second cylinder member 22
and the third cylinder member 23. When receiving an electric power,
the coil 35 develops a magnetic field around the coil 35. With the
development of the magnetic field, a magnetic circuit is formed in
the fixed core 30, the movable core 50, the first cylinder member
21, and the third cylinder member 23.
[0044] The first spring 31 is disposed such that one end of the
first spring 31 abuts against the movable core first end face 501
of the movable core 50. The other end of the first spring 31 abuts
against an end face 111 of an adjusting pipe 11 on the valve seat
255 side, and the adjusting pipe 11 is press-fixed to the inside of
the fixed core 30. The first spring 31 urges the movable core 50 in
a direction of the valve seat 255, that is, in the valve-closing
direction.
[0045] One end of the second spring 32 abuts against a spring seat
211 as a "slide member" provided in the first cylinder member 21.
The other end of the second spring 32 abuts against a regulating
unit second end face 452 of the regulating unit 45 on the valve
seat 255 side. The second spring 32 urges the needle 40 in the
valve-opening direction.
[0046] In the present embodiment, an urging force of the second
spring 32 is set to be smaller than an urging force of the first
spring 31. With the above configuration, when no electric power is
supplied to the coil 35, the seal portion 42 of the needle 40 is in
a state to abut against the valve seat 255, that is, in a valve
closing state.
[0047] The spring seat 211 is disposed on the valve seat 255 side
of the regulating unit 45 and radially outside of the shaft portion
41 separately from the first cylinder member 21. The spring seat
211 includes multiple members whose cross-section in a direction
perpendicular to the central axis CA0 is formed in an arc shape
centered on a point on the central axis CA0. The spring seat 211 is
slidable on the shaft portion 41.
[0048] A tubular fuel introduction pipe 12 is press-fitted and
welded on an end portion of the third cylinder member 23 opposite
to the second cylinder member 22 side. A filter 13 is disposed
inside of the fuel introduction pipe 12. The filter 13 collects
foreign matter contained in the fuel that flows from an
introduction port 14 of the fuel introduction pipe 12.
[0049] Radially outer sides of the fuel introduction pipe 12 and
the third cylinder member 23 are molded with a resin. A connector
15 is formed at the mold part. A terminal 16 for supplying an
electric power to the coil 35 is insert-molded in the connector 15.
A tubular holder 17 is disposed radially outside of the coil 35 so
as to surround the coil 35.
[0050] The fuel that flows from the introduction port 14 of the
fuel introduction pipe 12 flows inside of the fixed core 30, inside
of the adjusting pipe 11, through the flow channel 400 and the hole
411, and between the first cylinder member 21 and the shaft portion
41 and is introduced into the injection nozzle 25. In other words,
a path extending from the introduction port 14 of the fuel
introduction pipe 12 to a space between the first cylinder member
21 and the shaft portion 41 of the needle 40 configures the fuel
passage 18 for introducing the fuel into the injection nozzle
25.
[0051] Next, the operation of the fuel injection valve 1 will be
described. In the fuel injection valve 1, the distance by which the
needle 40 moves, that is, the lift quantity of the needle 40 is
different depending on a magnitude of a pressure of the fuel
flowing in the fuel passage 18. In this example, cases in which the
pressure of the fuel is relatively high and relatively low will be
described, separately.
[0052] First, when no electric power is supplied to the coil 35,
the seal portion 42 of the needle 40 abuts against the valve seat
255. In this situation, the needle 40, the movable core 50, and the
fixed core 30 have a positional relationship illustrated in FIG. 2.
Specifically, the urging force of the first spring 31 and the
urging force of the second spring 32 are exerted on the needle 40
and the movable core 50, the regulating unit first end face 451
abuts against the movable core second end face 502. In this
situation, the gap 430 is provided between the movable core first
end face 501 and the flange portion end face 431. In addition,
because no magnetic attraction force is generated between the fixed
core 30 and the movable core 50, a gap is provided between the end
face 303 of the fixed core abutting portion 302 and the movable
core first end face 501.
[0053] When the electric power is supplied to the coil 35, and a
magnetic attraction force is generated between the fixed core 30
and the movable core 50, the movable core 50 moves in the
valve-opening direction by a distance corresponding to a length of
the gap 430 in the central axis CA0 direction while accelerating.
As illustrated in FIG. 3, when the movable core first end face 501
abuts against the flange portion end face 431, because the movable
core 50 moving in the valve-opening direction while accelerating
collides with the flange portion 43, a relatively large force in
the valve-opening direction is exerted on the needle 40. In this
situation, a gap 450 is provided between the movable core second
end face 502 and the regulating unit first end face 451.
[0054] When the movable core 50 moves in the valve-opening
direction due to the magnetic attraction force in a state where the
movable core first end face 501 abuts against the flange portion
end face 431, the seal portion 42 is spaced apart from the valve
seat 255, and the injection holes 26 are opened. When the injection
holes 26 are opened, the fuel introduced into the injection nozzle
25 is injected toward the outside through the injection holes 26.
As illustrated in FIG. 4, when the movable core 50 that moves in
the valve-opening direction in a state where the movable core first
end face 501 abuts against the flange portion end face 431 abuts
against the fixed core abutting portion 302, the movement in the
valve-opening direction is stopped.
[0055] When the fuel flowing in the fuel passage 18 is of a
relatively high pressure, after the movable core 50 has abutted
against the fixed core abutting portion 302, the movable core first
end face 501 of the movable core 50 which abuts against the fixed
core abutting portion 302 remains abutted against the flange
portion end face 431 without moving the needle 40 in the
valve-opening direction. With the above configuration, as
illustrated in FIGS. 3 and 5, the lift quantity of the needle 40
when the fuel is of the relatively high pressure is represented by
a distance DH1 that is a distance from a position of the flange
portion end face 431 of the needle 40 when the seal portion 42
abuts against the valve seat 255 to a position of the end face 303
of the fixed core abutting portion 302. In FIG. 5, the position of
the needle 40 when the seal portion 42 abuts against the valve seat
255 is indicated by a dotted line.
[0056] On the other hand, when the fuel flowing in the fuel passage
18 is of a relatively low pressure, after the movable core 50 has
abutted against the fixed core abutting portion 302, the needle 40
further moves in the valve-opening direction due to the urging
force of the second spring 32. Specifically, as illustrated in FIG.
5, the needle 40 moves until the movable core second end face 502
of the movable core 50 that abuts against the fixed core abutting
portion 302 abuts the regulating unit first end face 451. With the
above configuration, the lift quantity of the needle 40 when the
fuel is of the relatively low pressure is represented by a distance
DL1 that is a distance from the position of the flange portion end
face 431 of the needle 40 where the seal portion 42 abuts against
the valve seat 255 to a position of the flange portion end face 431
illustrated in FIG. 5. Since the position of the flange portion end
face 431 illustrated in FIG. 5 is away from the valve seat 255 more
than the end face 303 of the fixed core abutting portion 302, the
distance DL1 is longer than the distance DH1.
[0057] When power supply to the coil 35 is stopped, the magnetic
attraction force between the fixed core 30 and the movable core 50
is vanished. When the fuel flowing in the fuel passage 18 is of the
relatively high pressure, the movable core 50 moves in the
valve-closing direction from a state illustrated in FIG. 4 due to
the urging force of the first spring 31, and the movable core
second end face 502 abuts against the regulating unit first end
face 451. After the movable core second end face 502 abuts against
the regulating unit first end face 451, the movable core 50 and the
needle 40 move in the valve-closing direction due to a difference
between the urging force of the first spring 31 and the urging
force of the second spring 32. Also, when the fuel flowing in the
fuel passage 18 is of the relatively low pressure, because the
movable core second end face 502 abuts against the regulating unit
first end face 451, the movable core 50 and the needle 40 move in
the valve-closing direction due to the difference between the
urging force of the first spring 31 and the urging force of the
second spring 32.
[0058] When the seal portion 42 of the needle 40 which moves in the
valve-closing direction abuts against the valve seat 255, the
movement of the needle 40 in the valve-closing direction is
stopped. As a result, the injection of the fuel from the injection
holes 26 is stopped.
[0059] In the fuel injection valve 1 according to the first
embodiment, when the seal portion 42 abuts against the valve seat
255, and the regulating unit first end face 451 abuts against the
movable core second end face 502, the gap 430 is provided between
the flange portion end face 431 and the movable core first end face
501. In the fuel injection valve 1, when the electric power is
supplied to the coil 35, the movable core 50 abuts against the
needle 40 while accelerating by a distance corresponding to the
length of the gap 430 in the central axis CA0 direction.
Accordingly, in the fuel injection valve 1, the relatively large
force in the valve-opening direction can be exerted on the needle
40.
[0060] In addition, in the fuel injection valve 1, the second
spring 32 that urges the needle 40 in the valve-opening direction
abuts against the regulating unit 45 disposed so as to be
reciprocatingly movable integrally with the shaft portion 41. In
the case where the fuel injection valve 1 opens the valve, when the
movable core 50 that moves in the valve-opening direction abuts
against the fixed core abutting portion 302 after having abutted
against the flange portion 43, the needle 40 is spaced apart from
the movable core 50 due to the urging force of the second spring
32, and further moves in the valve-opening direction. As a result,
the lift quantity of the needle 40 is longer than the distance by
which the movable core 50 moves until the movable core 50 abuts
against the fixed core abutting portion 302 since the movable core
50 abuts against the flange portion 43.
[0061] Up to now, in the fuel injection valve having the needle
supported to the movable core as in the fuel injection valve
disclosed in Patent Literature 1, when the injection quantity of
the fuel is increased with an increase in the lift quantity of the
needle, in order to increase the magnetic attraction force
generated between the fixed core and the movable core, there is a
need to increase the electric power to be supplied to the coil. On
the other hand, in the fuel injection valve 1 according to the
present disclosure, as described above, the lift quantity of the
needle 40 can be increased without any increase in the electric
power to be supplied to the coil 35. As a result, in the fuel
injection valve 1, the injection quantity of fuel can be increased
while suppressing an increase in the electric power to be supplied
to the coil 35.
[0062] FIG. 6 illustrates a relationship between the lift quantity
of the needle 40 and a force (hereinafter referred to as "valve
closing force") in the valve-closing direction to be exerted on the
needle 40. In FIG. 6, the axis of abscissa represents the lift
quantity of the needle 40, and the axis of ordinate represents the
valve closing force. In FIG. 6, a case in which a fuel flowing in
the fuel passage 18 is of a relatively high voltage is indicated by
a solid line LH1, and a case in which the fuel is of a relatively
low voltage is indicated by a solid line LL1.
[0063] When the lift quantity is "0", a difference between the
urging force of the first spring 31 and the urging force of the
second spring 32 as well as a force (hereinafter referred to as
"fuel pressure") of a value obtained by multiplying seat areas of
the seal portion 42 and the valve seat 255 by a pressure of the
fuel flowing in the fuel passage 18 is exerted on the needle 40 in
the valve-closing direction.
[0064] When the fuel flowing in the fuel passage 18 is of the
relatively high pressure, because the fuel pressure is relatively
high, even when the lift quantity of the needle 40 is the distance
DH1, that is, the movable core first end face 501 abuts against the
end face 303 of the fixed core abutting portion 302, the valve
closing force exerted on the needle 40 is relatively large.
Specifically, as illustrated in FIG. 6, the valve closing force is
larger than an urging force Fsp2 of the second spring 32. As a
result, when the fuel is relatively high, after the movable core 50
abuts against the fixed core abutting portion 302, the needle 40
does not move in the valve-opening direction even due to the urging
force of the second spring 32. Therefore, the lift quantity of the
needle 40 becomes the distance DH1.
[0065] On the other hand, when the fuel flowing in the fuel passage
18 is of the relatively low pressure, because the fuel pressure is
relatively low, when the lift quantity of the needle 40 becomes the
distance DH1, the valve closing force exerted on the needle 40
becomes smaller than the urging force Fsp2 of the second spring 32
as illustrated in FIG. 6. As a result, when the fuel is relatively
low, after the movable core 50 abuts against the fixed core
abutting portion 302, the needle 40 moves in the valve-opening
direction due to the urging force of the second spring 32.
Therefore, the lift quantity of the needle 40 becomes the distance
DL1 larger than the distance DH1.
[0066] As described above, in the fuel injection valve 1, the lift
quantity of the needle 40 is changed according to the pressure of
the fuel flowing in the fuel passage 18.
[0067] The fuel injection valve 1 includes the fixed core abutting
portion 302 having the same hardness as that of the movable core
50. As a result, in the opening/closing operation of the fuel
injection valve 1, the fixed core main body portion 301 is
prevented from being worn or damaged by the abutment against the
movable core 50. Therefore, a reduction in the performance and the
damage of the fuel injection valve 1 can be prevented.
[0068] The second spring 32 is gradually increased in the urging
force when the second spring 32 abuts against the valve seat 255
from a state where the needle 40 is spaced apart from the valve
seat 255. An impact when the needle 40 moving in the valve-closing
direction collides with the valve seat 255 can be reduced.
Therefore, the seal portion 42 and the valve seat 255 can be
prevented from being worn, deformed, or damaged.
[0069] The needle 40 slides on the spring seat 211 disposed on an
inner wall of the first cylinder member 21. With this
configuration, an unintentional fuel injection caused by a trouble
in the reciprocating movement such as an inclination of the needle
40 can be prevented.
Second Embodiment
[0070] Hereinafter, a fuel injection valve according to a second
embodiment of the present disclosure will be described with
reference to FIGS. 7 and 8. The second embodiment is different from
the first embodiment in that a flange portion accommodation member
is provided. The substantially same parts as those in the first
embodiment are denoted by identical reference numerals or symbols,
and their description will be omitted. FIGS. 7 and 8 illustrate a
valve-opening direction and a valve-closing direction in which the
valve-opening direction is a direction in which a needle 40 is
spaced apart from a valve seat 255 and the valve-closing direction
is a direction in which the needle 40 abuts against the valve seat
255.
[0071] A fuel injection valve 2 according to the second embodiment
includes a bottomed cylindrical member 60 as a "flange portion
accommodation member" that houses a flange portion 43 so as to be
reciprocatingly movable. FIG. 7 illustrates a main cross-sectional
view of the fuel injection valve 2 in a state where the needle 40
abuts against the valve seat 255, and a regulating unit first end
face 451 abuts against a movable core second end face 502. FIG. 8
illustrates a main cross-sectional view of the fuel injection valve
2 in a state where the lift quantity of the needle 40 is
maximum.
[0072] The bottomed cylindrical member 60 is disposed on a side of
the movable core 50 opposite to the valve seat 255 and inside of
the fixed core abutting portion 302 to be reciprocatingly movable
relative to the fixed core 30. The bottomed cylindrical member 60
is formed in a bottomed tubular shape, and includes a disc portion
61 as a "bottomed portion" and a cylinder portion 62. The disc
portion 61 and the cylinder portion 62 are integrally formed.
[0073] The disc portion 61 is located on a side of the flange
portion 43 opposite to the valve seat 255. The disc portion 61 is
formed such that its cross section perpendicular to the central
axis CA0 is formed in a circular shape. A communication passage 612
is provided in the disc portion 61, and communicates between an
inside and an outside of the bottomed cylindrical member 60. The
communication passage 612 defines a fuel passage 18, and discharges
the fuel inside the bottomed cylindrical member 60 toward the
outside due to the movement of the flange portion 43.
[0074] The cylinder portion 62 extends toward the valve seat 255
from a radial outside of the disc portion 61. An inner wall 621 of
the cylinder portion 62 is formed to be slidable on an outer wall
433 on the radial outside of the flange portion 43. The hardness of
the inner wall 621 is the same as that of the outer wall 433. An
outer wall 622 of the cylinder portion 62 is disposed to be
slidable on an inner wall 305 of the fixed core abutting portion
302. The hardness of the outer wall 622 is the same as that of the
inner wall 305.
[0075] One end of the cylinder portion 62 is fixed to the disc
portion 61. An end portion of the cylinder portion 62 opposite to
the end portion fixed to the disc portion 61 of the cylinder
portion 62 is disposed to be abuttable against the movable core 50.
The cylinder portion 62 has a length as long as the flange portion
43 can reciprocate inside the bottomed cylindrical member 60.
[0076] The first spring 31 is disposed such that one end of the
first spring 31 abuts against an end face 613 of the disc portion
61 on the side opposite to the valve seat 255. The first spring 31
urges the movable core 50 through the bottomed cylindrical member
60 in the direction of the valve seat 255, that is, in the
valve-closing direction.
[0077] The shaft portion 41 has a communication passage 410 that
communicates between a gap 430 and the flow channel 400. A fuel
that flows into or out of a gap 430 with a change in a length of
the gap 430 in a central axis CA0 direction passes through a
communication passage 410.
[0078] In the fuel injection valve 1, when the pressure of the fuel
flowing in the fuel passage 18 is relatively low, the needle 40
moves until the movable core second end face 502 abuts against the
regulating unit first end face 451 as illustrated in FIG. 8, after
the flange portion end face 431 abuts against the movable core
first end face 501. As a result, the needle 40 can move by a
distance longer than the distance by which the movable core 50
moves until the movable core 50 abuts against the fixed core
abutting portion 302 since the movable core 50 abuts against the
flange portion 43. Therefore, the second embodiment obtains the
same advantages as those in the first embodiment.
[0079] In addition, in the fuel injection valve 2, the needle 40
reciprocates while an outer wall 433 and an inner wall 621 slide on
each other. Therefore, the reciprocating movement of the needle 40
is guided. Also, the bottomed cylindrical member 60 reciprocates
while an outer wall 622 and an inner wall 305 slide on each other.
As a result, the reciprocating movement of the bottomed cylindrical
member 60 is guided. In this way, the reciprocating movement of the
needle 40 in the direction of the central axis CA0 is guided by the
bottomed cylindrical member 60 and the fixed core 30. Therefore, an
unintentional fuel injection caused by a trouble in the
reciprocating movement such as an inclination of the needle 40 can
be further prevented.
[0080] Also, in the fuel injection valve 2, the inner wall 621 of
the cylinder portion 62 has the same hardness as that of the outer
wall 433 of the flange portion 43. With this configuration, a wear
in the sliding between the cylinder portion 62 and the flange
portion 43 can be suppressed.
[0081] In addition, the outer wall 622 of the cylinder portion 62
has the same hardness as that of the inner wall 305 of the fixed
core abutting portion 302. With this configuration, a wear in the
sliding between the cylinder portion 62 and the fixed core abutting
portion 302 can be suppressed.
Third Embodiment
[0082] Hereinafter, a fuel injection valve according to a third
embodiment of the present disclosure will be described with
reference to FIGS. 9 and 10. The third embodiment is different from
the second embodiment in a portion abutted when a needle is most
lifted. The substantially same parts as those in the second
embodiment are denoted by identical reference numerals or symbols,
and their description will be omitted. FIGS. 9 and 10 illustrate a
valve-opening direction and a valve-closing direction in which the
valve-opening direction is a direction in which a needle 40 is
spaced apart from a valve seat 255 and the valve-closing direction
is a direction in which the needle 40 abuts against the valve seat
255.
[0083] In a fuel injection valve 3 according to the third
embodiment, a disc portion 61 of a bottomed cylindrical member 60
is formed so as to be abuttable against a shaft portion 41 and a
flange portion 43. Specifically, an end face 611 of the disc
portion 61 on the valve seat 255 side is formed to be abuttable
against an end face 412 of the shaft portion 41 on the side
opposite to the valve seat 255 and an end face 432 of the flange
portion 43 on the side opposite to the valve seat 255.
Incidentally, in the present embodiment, because an end face 412 is
flush with an end face 432, an end face 611 is flat.
[0084] In the fuel injection valve 3, a third spring 33 is disposed
on a valve seat 255 side of a movable core 50. One end of the third
spring 33 abuts against a movable core second end face 502. The
other end of the third spring 33 abuts against an inner wall 212 of
a first cylinder member 21. The third spring 33 urges the movable
core 50 in the valve-opening direction.
[0085] In the fuel injection valve 3, when a power supply to a coil
is stopped, and a magnetic attraction force is vanished, the needle
40 and the movable core 50 are moved in the valve-closing direction
due to an urging force of a first spring 31. When the seal portion
42 abuts against the valve seat 255, the movement of the needle 40
in the valve-closing direction is stopped whereas the movable core
50 further moves in the valve-closing direction due to an inertial
force. When the inertial force when the needle 40 is spaced apart
from the movable core 50 is larger than the urging force of the
third spring 33, the movable core 50 abuts against the regulating
unit 45, and the movement of the movable core 50 in the
valve-closing direction is stopped. In this situation, a gap 430 is
provided between a flange portion end face 431 and a movable core
first end face 501.
[0086] In the fuel injection valve 3, when the fuel flowing in the
fuel passage 18 is of the relatively low pressure, the needle 40
further moves in the valve-opening direction until the end faces
412 and 432 of the needle 40 abut against an end face 611 of the
bottomed cylindrical member 60 as illustrated in FIG. 10 after the
flange portion end face 431 abuts against the movable core first
end face 501. As a result, the needle 40 can move by a distance
longer than the distance by which the movable core 50 moves until
the movable core 50 abuts against the fixed core abutting portion
302 since the movable core 50 abuts against the flange portion 43.
Therefore, the third embodiment obtains the same advantages as
those in the second embodiment.
[0087] Further, in the fuel injection valve 3, when the movable
core 50 moves in the valve-closing direction from a state where the
movable core first end face 501 abuts against the flange portion
end face 431, a moving speed of the movable core 50 in the
valve-closing direction is decreased due to the urging force of the
third spring 33. As a result, even when the movable core 50 moving
in the valve-closing direction collides with the regulating unit
45, an impact of the collision can be reduced. Therefore, the
movable core 50 and the needle 40 can be prevented from being
damaged.
Fourth Embodiment
[0088] Hereinafter, a fuel injection valve according to a fourth
embodiment of the present disclosure will be described with
reference to FIG. 11. The fourth embodiment is different from the
first embodiment in that a third urging member is provided. The
substantially same parts as those in the first embodiment are
denoted by identical reference numerals or symbols, and their
description will be omitted. FIG. 11 illustrates a valve-opening
direction and a valve-closing direction in which the valve-opening
direction is a direction in which a needle 40 is spaced apart from
a valve seat 255 and the valve-closing direction is a direction in
which the needle 40 abuts against the valve seat 255.
[0089] In the fuel injection valve 4 according to the fourth
embodiment, a third spring 33 is disposed on the valve seat 255
side of a movable core 50. One end of the third spring 33 abuts
against a movable core second end face 502. The other end of the
third spring 33 abuts against an inner wall 212 of a first cylinder
member 21. The third spring 33 urges the movable core 50 in the
valve-opening direction.
[0090] In the fuel injection valve 4, when the movable core 50
moves in the valve-closing direction from a state where the movable
core first end face 501 abuts against the flange portion end face
431, a moving speed of the movable core 50 in the valve-closing
direction is decreased due to the urging force of the third spring
33, and an impact when the movable core 50 collides with the
regulating unit 45 can be reduced. Therefore, the fourth embodiment
can obtain the same advantages as those in the first embodiment,
and can prevent the movable core 50 and the needle 40 from being
damaged.
Another Embodiment
[0091] In the above embodiments, the slide member for guiding the
reciprocating movement of the shaft portion is provided. However,
the slide member may be omitted.
[0092] In the embodiments described above, the fixed core includes
the fixed core main body portion and the fixed core abutting
portion. However, the fixed core abutting portion may be
omitted.
[0093] In the third embodiment, in the bottomed cylindrical member,
the inner wall of the cylinder portion slides on the outer wall of
the flange portion and the outer wall of the tubular portion slides
on the inner wall of the fixed core abutting portion. However, the
inner wall and the outer wall of the cylinder portion may not slide
on the outer wall of the flange portion and the inner wall of the
fixed core abutting portion, respectively. The movement of the
needle in the valve-opening direction may be stopped.
[0094] In the embodiments described above, the flange portion and
the regulating unit are formed in the substantially toric shape.
However, the shape of the flange portion and the regulating unit is
not limited to the above configuration. The shape may be an
elliptical cylindrical shape or a polygonal cylindrical shape, and
the flange portion and the regulating unit may be disposed in a
protruding shape in the circumferential direction of the shaft
portion.
[0095] The above embodiments include the spring seat against which
one end of the second spring abuts, and which can slide on the
shaft portion. However, the spring seat may not slide on the shaft
portion.
[0096] The present disclosure has been described based on the
embodiments; however, it is understood that this disclosure is not
limited to the embodiments or the structures. The present
disclosure includes various modification examples, or modifications
within an equivalent range. In addition, various combinations or
forms, and other combinations or forms including only one element,
more than or less than one among these combinations or forms are
included in the scope or the technical scope of the present
disclosure.
* * * * *